Present day terminal equipment such as telephones need to be fabricated to have visible indicators. In many such telephones, a light emitting diode ("LED") is used as a source of light for such visible indicators. The LED light output is controlled by the telephone electronics and the light output is transmitted from the LED to the surface of the telephone to provide information to a user for example, to indicate that a particular telephone key pad or function is being used. It is advantageous for the light output at the surface of the telephone to have a wide angle output pattern so that the indicator can be seen easily by a user from a wide viewing angle.
In the prior art, in fabricating such indicators, an LED is mounted relatively close to the surface of the telephone so that light output from the LED only has to travel a short distance through a conductor, for example, a lightpipe, to reach the surface of the telephone. A lightpipe typically used in such prior art configurations is a cylindrical tube of plastic, for example, acrylic.
Newer technology used to fabricate telephones sometimes requires mounting LEDs further from the surface of the telephone than was previously the case in the prior art. When prior art, cylindrical tube lightpipes are used in the newer telephone configurations, light is output from the end of the lightpipe in a narrow angle output pattern and provides an unsatisfactorily narrow viewing angle.
In light of the above, there is a need in the art for a lightpipe which outputs light in a wide angle output pattern.